The Darwin scholar, John Greene, once summarised the Darwinian revolution as the triumph of a dynamic and non-teleological structuring of nature over static, teological systems: the triumph of chance and change over design and permanence, the triumph of objectivity in the life sciences, of secularism and naturalism over clericalism and the supernatural. The form of such a characterisation is familiar enough – perhaps too familiar in the sense that we are apt to take for granted the structuring of historical material through dichotomies and antitheses. Such has been the stuff of scientific as well as historical exposition. When Galileo launched his controversial defence of Copernican cosmology, he insisted on a dialogue between two chief world systems. When Darwin published his Origin of Species, he fortified his argument by contrasting the strengths of his own theory with the inadequacies of ‘separate creation’. Within the subsequent history of evolutionary mechanics other dichotomies have become part of the folklore of science: ‘In effect, only two theories of evolution have ever been put forward,’ writes John Maynard Smith, ‘one, originating with Lamarck ... the other originating with Darwin.’ Such reduction of the scientific corpus to patterns of mutual exclusivity doubtless tells us something about the strategy, if not the logic, of scientific corroboration. It is a form of reductionism which popular works on the historiography of science have done little to discourage. Thomas Kuhn’s The Structure of Scientific Revolutions envisaged competition between two rival and incommensurable ‘paradigms’ as the hallmark of a revolutionary period. A greater theoretical diversity and the science had to be regarded as immature and consigned to a pre-paradigm era. The discontinuity theses of Michel Foucault have lent themselves to a similar dualistic rigidity. Witness the use made of his ‘epistemes’ by N.C. Gillespie, who, in his recent study of Charles Darwin and the Problem of Creation (1979), implied that there were only two epistemes worth talking about: the ‘positivist’, with its exclusion of metaphysics and natural theology, and the ‘creationist’, which was ultimately, if not immediately, grounded in the supernatural.

These may be the dichotomies one takes for granted, reinforced as they so often are with a wealth of anecdote. ‘Theology and Parsondom’ were, for T.H. Huxley, ‘the natural and irreconcilable enemies of science’. His professional rival Richard Owen, by contrast, considered those blind to the beauty of design in nature to be suffering from ‘some, perhaps, congenital, defect of mind’. But the trouble with reduction to polar opposites is that what really gets excluded are the middle positions which, for the intellectual historian, are often the most revealing. Galileo’s predicament was surely intensified by virtue of there being at least three world systems: the cosmology of Tycho Brahe, in which the sun orbited the earth carrying the other planets with it, was an option sufficiently attractive to block the proof of Copernicus by the disproof of Ptolemy. In Darwin’s case, the contrast between transmutation of species and ‘separate creation’ takes on a different aspect according to whether the stress is placed on ‘separate’ or ‘creation’. Again, the two stereotypes of Darwinism and Lamarckism may have some value in controlling 20th-century options but they positively detract from an understanding of Darwin himself. The direct impact of environmental change producing a response from the organism was a prominent feature of the early drafts of Darwin’s theory, his caricature of Lamarck’s mechanism in terms of an organism’s successfully willing its own modification arguably blinding him to the extent to which he shared a number of Lamarck’s assumptions, including the inheritance of acquired characteristics. The naturalism/supernaturalism dichotomy by which the Darwinian revolution is often structured also excludes important middle positions: those of Baden Powell and Richard Owen, for example, who were perfectly happy to have divinely ordained creation through secondary causes even before Darwin’s theory was in print. And even T.H. Huxley, for all his busy anti-clericalism, would not go the whole way with the German monist Ernst Haeckel in denying a long-term purpose built into an original creation.

Such qualifications will be familiar to students of Early Victorian science. But until now one dichotomy has remained more or less intact: the contrast between a positivist philosophy of science shared by the avant-garde evolutionary naturalists and an idealist epistemology which found expression in the belief that vertebrates, for example, were designed around a structural ‘archetype’, a divine Idea, whose successive instantiations were visible in the fossil record. Unity of structure which, for the Darwinians, was to be evidence of common descent was, for Richard Owen, evidence for the unity of the divine mind.

The antithesis is not itself in question, for Darwin himself took particular exception to such transcendentalist flights: ‘N.B. The explanation of types of structure in classes – as resulting from the will of the deity, to create animals on certain plans – is no explanation – it has not the character of a physical law & is therefore utterly useless. – it foretells nothing because we know nothing of the will of the deity ... ’ What has now been questioned, and very cleverly so by Desmond in his Archetypes and Ancestors, is whether the conventional image of Owen slain by Huxley gives an accurate picture of the idealists’ contribution to the science of palaeontology. Historians of science have been tempted to say that idealist philosophies were instructive for the physical sciences in the 17th century, when Kepler, for example, imposed order on the planetary orbits by thinking God’s thoughts after him, but obstructive in the 19th century, when William Whewell, Louis Agassiz and Richard Owen resisted the transmutation of species. Desmond’s informed analysis points to a more subtle conclusion. An idealist metaphysic may not have contributed to the science of evolutionary mechanics, but it did make a contribution to the foundations of palaeontology.